Method and apparatus for automatic self-aligning docking of a couch with a magnetic resonance imaging scanner

ABSTRACT

A docking assembly connected to a movable couch ( 30 ) docks the couch with an imaging apparatus ( 10 ). Couch alignment surfaces ( 72 ) mate with corresponding alignment surfaces ( 64 ) of a connecting region ( 50 ) of the imaging apparatus ( 10 ) to define a docked position of the movable couch ( 30 ) with respect to the imaging apparatus. A docking sensor ( 160 ) detects the movable couch ( 30 ) approaching the docked position. A latch ( 82 ) mates with the connecting region ( 50 ) of the imaging to apparatus ( 10 ). An actuator ( 130, 154 ) cooperates with the latch ( 82 ) to bias the movable couch ( 30 ) into the docked position responsive to a signal produced by the docking sensor ( 160 ).

The following relates to the diagnostic imaging arts. It particularlyrelates to the docking and undocking of a couch or other movable subjectsupport with a magnetic resonance imaging apparatus. The followingrelates more generally to rapid, safe, precise, and convenient transferof a patient or other imaging subject into and out of various types ofdiagnostic imaging scanners such as magnetic resonance imaging scanners,computed tomography imaging scanners, nuclear cameras, positron emissiontomography scanners, and the like.

In medical diagnostic imaging, an issue arises in the transfer of animaging subject to and from the imaging apparatus. In many cases, thesubject is disabled and unable to assist in the transfer process. Insome instances it is important to preserve patient position.

Typically, the patient is placed on a wheeled patient couch or othermovable subject support that is adapted to mechanically dock with themedical diagnostic magnetic resonance imaging scanner or other imagingapparatus. In one known approach, a locking mechanism that locks thecouch to the imaging apparatus is triggered by operation of a brakepedal of the patient couch. Once connected, a conveyor belt of theimaging apparatus is linked with a patient supporting pallet or top ofthe patient couch, and the patient and pallet are transported into amagnet bore of the magnetic resonance imaging apparatus for imaging.

After the imaging session is complete, the patient and pallet aretransported back and reconnected to the patient couch base. The operatordisconnects the conveyor belt of the imaging apparatus from the patientcouch. The brake pedal is released, which also unlocks the patient couchfrom the subject support, and the patient couch is wheeled away.

These patient transfer systems rely upon substantial operator input andcoordination to dock and undock the patient successfully. The couch ismanually aligned and moved into the docking position, and the lockingmechanism of the couch with the imaging apparatus relies upon accuracyof such manual alignment. Moreover, there is a substantial possibilityof operator error causing patient injury and/or damage to the couchand/or imaging apparatus if, for example, the couch is undocked prior todisconnection of the conveyor belt linkage.

The present invention contemplates an improved apparatus and method thatovercomes the aforementioned limitations and others.

According to one aspect, a docking assembly is disclosed. The dockingassembly is connected to a movable subject couch for docking the movablesubject couch with an imaging apparatus. Couch alignment surfaces matewith corresponding imaging apparatus alignment surfaces of a connectingregion of the imaging apparatus to define a docked position of themovable subject couch with respect to the imaging apparatus. A dockingsensor detects the movable subject couch approaching the dockedposition. A latch mates with the connecting region of the imagingapparatus. An actuator cooperates with the latch to bias the movablesubject couch into the docked position in response to the docking sensordetecting that the couch has approached the docking position.

According to another aspect, a method is provided for docking a movablesubject support couch with an imaging apparatus. The movable subjectsupport couch is moved toward the imaging apparatus. Responsive to themoving, a latch connected with the movable subject support couch mateswith a connecting region of the imaging apparatus. The movable couchapproaching a docked position with respect to the imaging apparatus isdetected. Responsive to the detecting, the movable subject support couchis biased into the docked position using the mated latch as a firstforce anchor.

One advantage resides in reduced operator actions involved in subjectdocking and undocking.

Another advantage resides in a reduced likelihood of damage to thepatient support and/or the imaging apparatus due to operator error inthe docking or undocking.

Yet another advantage resides in improved docking and undockingreliability.

Still yet another advantage resides in self-alignment of the couch orother movable subject support with the imaging apparatus.

Numerous additional advantages and benefits will become apparent tothose of ordinary skill in the art upon reading the following detaileddescription of the preferred embodiments.

The invention may take form in various components and arrangements ofcomponents, and in various process operations and arrangements ofprocess operations. The drawings are only for the purpose ofillustrating preferred embodiments and are not to be construed aslimiting the invention.

FIG. 1 shows a side view of a magnetic resonance imaging apparatus witha movable couch docked therewith.

FIG. 2 shows a partial sectional view of the magnetic resonance imagingapparatus and docked movable couch of FIG. 1.

FIG. 3 shows a connecting region of the magnetic resonance imagingapparatus of FIGS. 1 and 2 that cooperates with a docking assembly ofthe movable couch in docking the movable couch with the magneticresonance imaging apparatus.

FIG. 4 shows an overhead perspective view of a lower portion of themovable couch including components of the docking assembly.

FIG. 5 shows a perspective view from below of the lower portion of themovable couch shown in FIG. 4.

FIG. 6 shows a perspective view of a portion of the docking assemblyincluding an actuator, connecting rods, mechanical fittings, a springcartridge assembly, a divider plate, and latches.

FIG. 7 shows a perspective view of one of the latches including a guideplate.

FIG. 8 shows a perspective view of the latch of FIG. 7 with the guideplate removed.

FIG. 9 diagrammatically shows a state diagram of a state machinecontroller that controls the docking and undocking processes.

With reference to FIGS. 1 and 2, a magnetic resonance imaging apparatus10 includes a housing 12 that encloses at least a main magnet which ispreferably superconducting and cryoshrouded. The housing 12 defines abore 14 inside which a subject is placed for imaging. Magnetic fieldgradient coils for spatially encoding the magnetic resonance signals areenclosed in the housing 12 or are arranged in the bore 14, as are one ormore radio frequency coils and other optional components that arecooperatively used to generate, tailor, and detect magnetic resonancesignals of the imaging subject.

A motorized belt or chain drive 20 passes through the bore 14. The belt20 is linearly movable to position or move an imaging subject axiallywithin the bore 14. The motorized belt 20 includes a portion 22extending beyond a first side 24 of the housing 12 to enable the subjectto be positioned with a portion extending outside the bore 14 on thefirst side 24.

On a second side 26 of the housing 12, the belt 20 cooperates with amovable subject support pallet or couch top 28 of a couch assembly 30 todefine a continuous motorized subject transport that extends on bothsides 24, 26 of the housing 12. Specifically, a coupling element 32couples the belt 20 of the magnetic resonance imaging apparatus 10 witha subject support belt portion 34.

The movable couch 30 is detachably attached to the imaging apparatus 10.To enable the couch 30 to be moved when it is detached from the imagingscanner 10, the couch 30 includes wheels 40, rolling castors, or thelike. One or more wheel brakes 42 are selectively operated to immobilizethe couch 30. Preferably, the couch 30 also includes a height adjustmentmechanism 44 for vertically aligning the coupling element 32 with thebelt 20 of the imaging apparatus 10.

With continuing reference to FIGS. 1 and 2, and with further referenceto FIG. 3, the magnetic resonance imaging apparatus 10 includes aconnecting region 50 that provides alignment and force anchoring foraligning and securing the movable couch 30 with the imaging apparatus10. In the illustrated embodiment, the connecting region 50 includes twolatching blocks 52 on opposite sides of an electronic connector 54. Theelectrical connector 54 provides for optional electrical communicationbetween the imaging apparatus 10 and the movable couch 30, for exampleto communicate sensor readings therebetween or to deliver electricalpower and/or control signals from the imaging apparatus 10 to themovable couch 30. Each latching block 52 includes a camming surface 56for camming a latch or other mating component of the subject support 30onto the latching block 52.

Placement of the two latching blocks 52 on opposite sides of theelectrical connector 54 advantageously arranges the force anchoringsymmetrically with respect to the imaging apparatus 10. However, if theoptional electrical connector 54 is omitted, a single centrallypositioned latching block can be employed. Of course, more than twolatching blocks can also be included to provide additional forceanchoring points.

The connecting region 50 also includes a tongue 60 that extends awayfrom the imaging apparatus 10. The tongue 60 includes camming surfaces62 for facilitating lateral alignment of the couch 30 with the imagingapparatus 10 during docking. The tongue 60 further includes alignmentsurfaces 64 disposed on the tongue edges that cooperate withcorresponding surfaces of the docking assembly to define a dockedposition with the movable couch 30 in line with the bore 14. A mountingplate 66 secures the connecting region 50 with the second side 26 of theimaging apparatus 10. Alternatively, the connecting region 50 can beintegrated with the housing 12. Preferably, the connecting region 50includes stops 68 that limit movement of the couch 30 toward the imagingapparatus 10 and limit skewing to assure that the couch 30 is in linewith the bore 14.

With continuing reference to FIGS. 1-3 and with further reference toFIGS. 4-8, a lower portion 70 of the movable couch 30 includes a dockingassembly that cooperates with the connecting region 50 of the magneticresonance imaging apparatus 10 to detachably secure the movable couch 30with the magnetic resonance imaging apparatus 10. The docking assemblyincludes alignment surfaces 72 with rollers or bearings 74 thatcooperate with the alignment surfaces 64 of the tongue 60 of theconnecting region 50 of the imaging apparatus 10 to define the dockedposition of the movable couch 30 respective to the imaging apparatus 10.The rollers or bearings preferably also serve as camming surfaces thatcooperate with the camming surfaces 62 of the tongue 60 of theconnecting region 50 to urge the movable couch 30 laterally toward thedocked position as the couch 30 approaches the imaging apparatus 10.

The docking assembly further includes latches 82 disposed at a forwardend 84 of the couch 30 that detachably latch with the two latchingblocks 52. In the illustrated embodiment, there are two latches 82corresponding to the two latch blocks 52. An alternative embodiment witha single centrally located latch block will typically include a singlecorresponding latch, rather than the two latches shown.

In the illustrated embodiment, each latch 82 includes a hook 86 that isspring-biased to a closed position by a leaf spring 88. (Best seen inFIGS. 7 and 8). The leaf spring 88 is secured to a guide block 90 at oneend, and is preferably secured to the hook 86 by a fastener 92. Theguide block is secured to the lower portion 70 of the movable couch 30.(Best seen in FIG. 5). The hook 86 of each latch 82 pivots about aclevis pin 94 that in turn is connected with a clevis yoke 96 to allowthe hook 86 to open in opposition to the biasing force produced by theleaf spring 88.

The clevis yoke 96 is fastened to a guide rod 100 that slidably passesthrough the guide block 90. A guide plate 102 is secured to the guideblock 90 via fasteners 104. (Note that the guide plate 102 is shown inFIG. 7, and is removed in FIG. 8 to show underlying components). Theguide plate 102 includes a first narrow slot 106 that cams the clevispin 94, and a second wider slot 108 that cooperates with a camming pin110 to guide opening and closing of the latch 82.

The guide rod 100 of each of the two latches 82 connects with a dividerplate 114 that distributes an actuator force between the two latches 82.As shown in FIG. 6, ends of the guide rods 100 can connect to thedivider plate 114. Alternatively, as shown in FIG. 5, each guide rod 100can connect at an intermediate point such that the guide rod 100 alsopasses through a caster weldment of the couch 30 to assist in guidingand dividing actuator force between the two guide rods 100.

The divider plate 114 in turn connects with a front connecting rod 120via a pivotable clevis block 122 that is pinned to the divider plate114. The front connecting rod 120 includes a threaded opposite end thatthreads into a spring cartridge assembly 130. A rear connecting rod 134has a threaded end that threads into the spring cartridge assembly 130and extends away from the forward end 84 of the movable couch 30 througha guide block 136 toward a rear end 138 of the couch 30. The rearconnecting rod 134 connects with another clevis block 142 that is pinnedto a pivotable drive link 146. The pivotable drive link pivots about apivot 150 fixed to the weldment of the movable couch 30.

An actuator motor 154 delivers the actuator force to the pivotable drivelink 146 at an end of the drive link 146 opposite the pivot 150. Asecond class lever is thus defined in which the load-coupling clevisblock 142 is arranged between the applied force produced by the actuatormotor 154 and a lever fulcrum defined by the pivot 150. The hooks 86 arecammed apart during movement of the couch 30 and are biased by the leafsprings 88 onto the blocks 52. To undock, the actuator motor 154 appliesa force to the linkage which moves the hooks 86 apart, away from theblocks 52. In one suitable embodiment, the actuator motor 154 is abattery-driven 24 volt self-locking linear actuator motor.

With continuing reference to FIGS. 1-8, the docking assembly furtherincludes various sensors for sensing various stages of docking andundocking. In the illustrated embodiment, these sensors include a startdock sensor 160 suitably embodied as a plunger switch that is activatedor turned on (that is, plunger depressed) when the movable couch 30approaches the docked position such that the plunger contacts a surfaceof the connecting region 50 of the imaging apparatus 10. A flipperswitch 162 similarly detects when the movable couch 30 is secured in thedocked position, and when the couch 30 is substantially free from thedocked position during undocking. A brake switch detects whether thewheel brake 42 is on or off.

Optical switch sensors 164 indicate a state of the drive link 146. In apreferred embodiment, three drive link optical switch sensors 164indicate whether the drive link 146 is in: (i) an undocked position inwhich the drive link 146 is pivoted toward the rear end 138 of the couch30; (ii) a docked position in which the drive link 146 is pivoted towardthe front end 84 of the couch 30; or (iii) a ready-to-dock position inwhich the drive link 146 is pivoted into an intermediate positionbetween the front end 84 and the rear end 138 of the couch 30.

With continuing reference to FIGS. 1-8 and with further reference toFIG. 9, the docking assembly preferably includes a state machinecontroller whose state diagram 200 is schematically represented in FIG.9. The state machine controller is preferably embodied by amicroprocessor or microcontroller disposed on the movable couch 30 thatmonitors the sensors and implements the state diagram 200.

The exemplary state diagram 200 includes four states. In a ready-to-dockstate 202, the optical sensor 164 indicates the ready-to-dock positionof the drive link 146, and the start dock plunger sensor 160, theflipper switch 162, and the brake switch are off. In a docked state 204,the optical sensor 164 indicates the docked position of the drive link146, the start dock plunger sensor 160 and the flipper switch 162 areboth activated, but the brake switch is off. A docked-and-braked state206 is similar to the docked state 204 except that the brake sensorindicates the brake is on. In an undocked state 208, the optical sensor164 indicates the undocked position of the drive link 146, the flipperswitch 162 is activated, and the brake switch is off.

The exemplary state diagram 200 suitably implements a docking processthat starts at the ready-to-dock state 202. An operator rolls themovable couch 30 on its wheels 40 toward the connecting region 50 of theimaging apparatus 10. During this movement, the camming surfaces 62 ofthe connecting region 50 of the imaging apparatus 10 contact and camwith the rollers 74 or other camming surfaces of the docking assembly tourge the couch 30 toward the docked position. Similarly, the hooks 86 ofthe latches 82 contact the camming surfaces 56 of the latch blocks 52 ofthe connecting region 50 and cam open against the biasing force exertedby the leaf springs 88. As continued movement of the couch 30 moves thehooks 86 past the camming surfaces 56, the hooks 86 close onto thelatching blocks 52 due to the biasing of the leaf springs 88.

Continued movement of the couch 30 toward the docked position causes thestart dock plunger 160 to be pushed in, triggering a transition from theready-to-dock state 202 to the docked state 204. The actuator motor 154is driven to pivot the drive link 146 from the ready-to-dock position tothe docked position. This movement produces an actuator force F₁ pullingon the rear connecting rod 134. Initially, the actuator force F₁transfers through the rear connecting rod 134, the spring cartridgeassembly 130, and the front connecting rod 120, and is distributed bythe divider plate 114 and the guide rods 100 to the two latches 82.Thus, the actuator force F₁ is a tensile force acting between a rearforce anchor point corresponding to the motor 154 and the drive link146, and a front force anchor point defined by the connection of thelatches 82 onto the latch blocks 52.

The tensile actuator force F₁ draws the movable couch 30 into the dockedposition. Once docked, the motor 154 continues to operate to transferand store a predetermined amount of mechanical energy in the springcartridge assembly 130. In a preferred embodiment, the spring cartridgeassembly 130 is loaded to about 55 kg. Once the spring cartridgeassembly 130 is loaded to the desired value, the motor 154 ceasesoperation.

Thus, when the motor 154 ceases operation the movable couch 30 remainsbiased and secured in the docked position by the loaded spring cartridgeassembly 130. The docked state 204 is indicated by the optical sensors164. To ensure the movable couch 30 is secured, the user is preferablyprompted by a display or other indicator to engage the brakes. Theoperator engages the wheel brake 42. Engaging the wheel brake 42activates the brake switch and places the docking assembly into thedocked-and-braked state 206.

Once docked and braked, the operator connects and locks the beltcoupling element 32 to the belt 20 of the imaging apparatus 10. Once theconnection is sensed, a lock which locks the subject pallet or couch top28 to the couch 30 is released. The belt 20 transfers the subject pallet28 into the magnet bore 14 of the imaging apparatus 10. The operatorcauses the imaging apparatus 10 to perform selected magnetic resonanceimaging operations on the subject, and transfers the subject back to themovable couch 30 via the linked belts 20, 34.

Once the pallet 28 is locked to the couch 30, the operator can initiateundocking by decoupling the coupling element 32 and releasing the wheelbrake 42. Preferably, transition from the docked-and-braked state 206 tothe undocked state 208 is initiated by release of the wheel brake 42.However, the transition preferably also is contingent upon a tabletopsensor 212 (operatively represented in FIG. 9) indicating that theconveyor belt coupling element 32 is unlocked and the pallet 28 islocked to the couch 30. This reduces the likelihood of damage to theconveyor belts 20, 34 or the coupling element 32.

To undock, the motor 154 operates in a reverse direction to pivot thedrive link 146 from the rearward docked position to the forward undockedposition. This exerts an actuator force F₂ on the rear connecting rod134 directed toward the front end 84. Initially, the actuator force F₂transfers through the rear connecting rod 134 to the spring cartridgeassembly 130 to unload the spring cartridge assembly 130. That is, inthe exemplary embodiment the 55 kg stored in the spring cartridgeassembly 130 is unloaded.

Once the spring cartridge assembly 130 is unloaded, the actuator forceF₂ transfers through the rear connecting rod 134, the spring cartridgeassembly 130, and the front connecting rod 120, and is distributed bythe divider plate 114 and the guide rods 100 to the two latches 82. Theactuator force F₂ drives each hook 86 forward. During this forwardmotion, the clevis pin 94 cams in the first narrow slot 106 and thecamming pin 110 cams in the second wider slot 108 of the guide block 90to guide the hook 86 into an open position against the biasing force ofthe leaf spring 88.

When the drive link 146 reaches the undocked position as indicated bythe drive link optical switch sensors 164, the latches 82 are retainedin the open position. The operator can then move the couch 30 away fromthe imaging apparatus 10. The movement draws the opened latches 82 pastthe latch blocks 52 of the connection region 50 of the imaging apparatus10. Continued movement causes the flipper switch 162 to deactivate,indicating that the latches 82 are clear of the latching blocks 52.

Deactivation of the flipper switch 162 initiates a transition from theundocked state 208 to the ready-to-dock state 202. To make thistransition, the motor 154 moves the drive link 146 from the undockedposition to the intermediate ready-to-dock position. The movementtransfers through the rear connecting rod 134, the spring cartridgeassembly 130, and the front connecting rod 120, and is distributed bythe divider plate 114 and the guide rods 100 to the two latches 82. Theactuator force F₂ holding the hooks 86 open is released so that theclosing bias provided by the leaf springs 88 causes the hooks 86 to bebiased into the closed position.

Docking and undocking of the movable couch 30 with the exemplarymagnetic resonance imaging apparatus 10 is described herein. However,those skilled in the art can readily adapt the described dockingassembly to perform docking and undocking of a patient couch or othermovable imaging subject support with other types of magnetic resonanceimaging scanners, or with a computed tomography imaging apparatus, anuclear camera, a positron emission tomography imaging apparatus, aradiotherapy apparatus, or the like.

1. A docking assembly connected to a movable subject couch for docking amovable subject couch with an imaging apparatus, the docking assemblyincluding: couch alignment surfaces that mate with corresponding imagingapparatus alignment surfaces of a connecting region of the imagingapparatus to define a docked position of the movable subject couch withrespect to the imaging apparatus; a docking sensor that detects themovable subject couch approaching the docked position; a latch thatmates with the connecting region of the imaging apparatus; and anactuator that cooperates with the latch to bias the movable subjectcouch into the docked position in response to the docking sensordetecting that the couch has approached the docking position.
 2. Thedocking assembly as set forth in claim 1, further including: rollingelements arranged between the couch alignment surfaces and thecorresponding imaging apparatus alignment surfaces of the connectingregion of the imaging apparatus.
 3. The docking assembly as set forth inclaim 1, wherein the docking assembly further includes: couch cammingsurfaces that cooperate with camming surfaces of the connecting regionof the imaging apparatus to cam the movable subject couch laterallytoward alignment with the docked position as the movable subject couchapproaches the imaging apparatus.
 4. The docking assembly as set forthin claim 1, wherein the latch includes: a biasing spring; and a hookthat is biased by the biasing spring toward a closed position, the hookbeing cammed opened in opposition to the biasing spring by a cammingsurface of a latch block as the movable subject couch approaches thedocked position, the biasing spring biasing the hook to close onto thelatch block as the hook moves past the camming surface and ceasescontact therewith.
 5. The docking assembly as set forth in claim 1,wherein the actuator includes: an electric motor; and a mechanicalenergy storage element interposed between the motor and the latch, themechanical energy storage element cooperating with the latch to bias themovable subject couch into the docked position when the motor is notdelivering mechanical energy.
 6. The docking assembly as set forth inclaim 5, wherein the mechanical energy storage element includes a springinterposed between the motor and the latch.
 7. The docking assembly asset forth in claim 6, wherein the actuator further includes: a driveshaft arranged between the motor and the latch, the motor driving thedrive shaft in a first direction to secure the latch onto the latchblock of the connecting region of the imaging apparatus, the springstoring energy received from the motor during the driving in the firstdirection, the stored energy continuing to bias the latch on the latchblock after the driving in the first direction ceases.
 8. The dockingassembly as set forth in claim 7, further including: an undock cammingsurface that communicates with the latch to cam the latch open when themotor drives the drive shaft in a second direction opposite the firstdirection.
 9. The docking assembly as set forth in claim 1, furtherincluding: an electronic controller communicating with the actuator andthe docking sensor, the electronic controller operating the actuator tocooperate with the latch to bias the movable subject couch into thedocked position in response to the docking sensor detecting the movablesubject couch approaching the docked position.
 10. The docking assemblyas set forth in claim 9, wherein the electronic controller monitors astate of the docking assembly, the docking assembly being in one of aplurality of states including: a ready-to-dock state in which the latchis biased into a closed position and the electronic controller iswaiting for the docking sensor to detect the movable subject couchapproaching the docked position; a docked state in which the latch isbiased into the closed position and secured to the connecting region bythe actuator; and an undocking state in which the latch is biased intoan open position by the actuator.
 11. The docking assembly as set forthin claim 10, further including: a tabletop lock sensor that indicates alocked condition of a subject transfer pallet of the movable subjectcouch, the electronic controller monitoring the tabletop lock sensor andprohibiting a docking assembly state transfer from the docked state tothe undocking state when the tabletop lock sensor indicates an unlockedcondition.
 12. The docking assembly as set forth in claim 10, furtherincluding: an actuator sensor that indicates a position of the actuator,the electronic controller identifying the docking assembly state basedon at least the docking sensor and the actuator sensor.
 13. A magneticresonance imaging apparatus including: a housing that houses at least amain magnet and magnetic field gradient coils and defines a bore; andthe connecting region of the docking assembly as set forth in claim 1secured to the housing.
 14. The magnetic resonance imaging apparatus asset forth in claim 13, wherein the connecting region further includes: atongue extending from the housing, the tongue defining the imagingapparatus alignment surfaces; and a latch block disposed on the tongue,the latch selectively latching onto the latch block.
 14. A couchincluding: a wheeled subject supports; and a docking assembly set forthin claim 1 for docking the wheeled subject support with a diagnosticimaging apparatus.
 15. The couch as set forth in claim 14, wherein theactuator includes: a motor disposed on the movable subject support thatselectively drives the latch to mate with the connecting region of theimaging apparatus.
 16. The couch as set forth in claim 15, wherein theactuator further includes: a spring disposed between the motor and thelatch, the spring being mechanically loaded when the motor drives thelatch to mate with the connecting region, the loaded spring biasing thelatch into the mated position when the motor ceases the driving.
 17. Amethod for docking a movable subject support couch with an imagingapparatus the method including: moving the movable subject support couchtoward the imaging apparatus; responsive to the moving, mating a latchconnected with the movable subject support couch with a connectingregion of the imaging apparatus; detecting the movable couch approachinga docked position with respect to the imaging apparatus; and responsiveto the detecting, biasing the movable subject support couch into thedocked position using the mated latch as a first force anchor.
 18. Themethod as set forth in claim 17, further including: locking a couchbrake after the movable couch his biased into the docked position; andresponsive to an unlocking of the couch braked, removing the biasing ofthe movable couch into the docked position and unmating the latch 1fromthe connecting region of the imaging apparatus.
 19. The method as setforth in claim 17, wherein the biasing of the movable subject supportcouch into the docked position includes: relatively drawing a secondforce anchor disposed on the movable couch toward the first force anchordefined by the mated latch.